Despite it's popularity, shares of 'Pokémon GO' are dropping.

FOX's Carole Zimmer has the details:

After making its debut in the U.S. earlier this month, the release of 'Pokémon GO' almost doubled Nintendo's stock. But there are other companies involved. Nintendo is a part owner of Niantic, the developer and distributor of the game.

Nintendo is also part owner of Pokémon company, which controls the merchandising of Pokémon characters. That means the revenue from the success of the Pokémon craze will be shared.

Carole Zimmer, FOX News.

Follow Carole Zimmer on Twitter: @carole_zimmer